A visible light communications technology is a new wireless optical communications technology developed based on an LED technology. Communication is performed through high-frequency blinking of an LED light source, and a transmission rate of visible light communication reaches up to 1 gigabit per second. There are quite abundant spectrum resources in the visible light communication. No general wireless communication, including microwave communication, can compare with this. In addition, the visible light communication may be applicable to any communications protocols and any environments, and a visible light communications device features flexible and convenient deployment and low costs, and is suitable for large-scale widespread application.
Visible light is used for short-distance communication in a visible light communications system. The visible light has high directivity and cannot penetrate an obstacle, and therefore is more secure compared with a wireless communication mode. Currently, some visible light communications systems have been put into application, such as a photonic access control system and photonic payment in the photonic Internet of Things. With increasing popularization of portable devices such as a mobile phone, the mobile phone may be used as a photonic client by using a flash function of the mobile phone. This greatly lowers an application threshold of the visible light communication. In addition, the mobile phone is originally carried around by a user, and therefore no additional burden is caused to the user.
However, daily visible light communication performed by a portable photonic client such as a mobile phone is generally in an environment with ambient light. When receiving an optical signal transmitted by the photonic client, a photonic receive end converts the optical signal into a meaningful electrical signal through photoelectric conversion. However, under exposure to the ambient light, the photonic receive end still converts the meaningless ambient light into useless electrical signals. These useless electrical signals are noise signals, and prevent a photonic receiver from correctly receiving an optical signal transmitted by the photonic client.
Therefore, a technology for improving optical signal reception is urgently needed in the art.